BirdieSync is THE tool to sync Tb with other devices. But without Tb, no sync is possible. Why no Tb ? Because my computer is not 24/7 connected. Because mobility is now the most important criteria. And because Tb dev is now freeze ! Now new feature, no improvement. Just updates for gecko.

Currently, I can't use BS anymore (I bought it 4 years ago, for an HTC TyTnII) because I don't have wifi nor 3G where I work and I will probably no longer used Tb within few months. I think my behavior is far from atypical.

So, for all your users but also BirdieSync future, you have to provide alternatives synchronization. For example online tool, standalone app, direct sync between Android/iOS/WM devices...

PS : I want a alternative to Google because I really don't want Google make links between all my contacts and friends.